Sedimentation settings and evolution history of the Kuril Basin (Sea of Okhotsk) in the Cenozoic

A study of the rocks from the Cenozoic sedimentary cover of the Kuril Basin slopes revealed two sedimentation stages in this area: the Late Oligocene-Early Miocene and Late Miocene-Pleistocene, which are separated by erosion in the Middle Miocene. They are characterized by dominant siliceous and terrigenous sediments, respectively. The former largely accumulated in neritic settings, while the latter were deposited in the bathyal zone under a strong influence of explosive volcanism. The change in the sedimentation regime probably occurred in the Middle-Late Miocene during the formation of the slopes of the present-day Kuril Basin. The rocks constituting crustal blocks with a granite-metamorphic layer served as a source of terrigenous material for the Cenozoic sedimentary cover, which indicates the sialic nature of the underlying basement.